Juniper JN0-351 Online Practice Questions and Exam Preparation

Juniper JN0-351 Online Questions & Answers

• Question 101:

  Exhibit.

  

  You want to verify prefix information being sent from 10.36.1.4.

  Which two statements are correct about the output shown in the exhibit? (Choose two.)

  A. The routes displayed have traversed one or more autonomous systems.
  B. The output shows routes that were received prior to the application of any BGP import policies.
  C. The output shows routes that are active and rejected by an import policy.
  D. The routes displayed are being learned from an I BGP peer.
  A. The routes displayed have traversed one or more autonomous systems.
  B. The output shows routes that were received prior to the application of any BGP import policies.

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  Explanation/Reference:

  The output shown in the exhibit is the result of the command "show ip bgp neighbor 10.36.1.4 received-routes", which displays all received routes (both accepted and rejected) from the specified neighbor.

  Option A is correct, because the routes displayed have traversed one or more autonomous systems. This can be seen from the AS_PATH attribute, which shows the sequence of AS numbers that the route has passed through. For example,

  the route 10.0.0.0/8 has an AS_PATH of 65001 65002, which means that it has traversed AS 65001 and AS 65002 before reaching the local router.

  Option B is correct, because the output shows routes that were received prior to the application of any BGP import policies. This can be seen from the fact that some routes have a status code of "r", which means that they are rejected by an

  import policy. The"received-routes" keyword shows the routes coming from a given neighbor before the inbound policy has been applied. To see the routes after the inbound policy has been applied, the "routes" keyword should be used

  instead. Option C is incorrect, because the output does not show routes that are active and rejected by an import policy. The status code of "r" means that the route is rejected by an import policy, but it does not mean that it is active. The

  status code of ">" means that the route is active and selected as the best path. None of the routes in the output have both ">" and "r" status codes.

  Option D is incorrect, because the routes displayed are not being learned from an IBGP peer. An IBGP peer is a BGP neighbor that belongs to the same AS as the local router. The output shows that the neighbor 10.36.1.4 has a remote AS of

  65001, which is different from the local AS of 65002. Therefore, the neighbor is an EBGP peer, not an IBGP peer.

• Question 102:

  You were provided a network diagram that told you to number your network from the 191.255.0.0/16 space. OSPF is enabled and adjacencies are up, but no routers are learning any routes. What can explain this?

  A. The default OSPF export policies advertise nothing, so you need to apply export policy
  B. The default OSPF import policy rejects all OSPF routes, so you need to apply import policy
  C. You need to modify the martian table with a 191.255.0.0/16 accept statement
  D. You need to enable OSPF on the lo0 interface to provide a route to the RID of each router in the network
  C. You need to modify the martian table with a 191.255.0.0/16 accept statement

• Question 103:

  What is the default keepalive time for BGP?

  A. 10 seconds
  B. 60 seconds
  C. 30 seconds
  D. 90 seconds
  B. 60 seconds

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  Explanation/Reference:

  The default keepalive time for BGP is 60 seconds1. The keepalive time is the interval at which BGP sends keepalive messages to maintain the connection with its peer1. If the keepalive message is not received within the hold time, the connection is considered lost1. By default, the hold time is three times the keepalive time, which is 180 seconds1.

• Question 104:

  You are configuring OSPF and want to ensure that interface ge-0/0/3 is preferred over interface ge-0/0/4.

  Which statement is correct in this scenario?

  A. Configure ge-0/0/3 with a higher metric.
  B. Configure reference bandwidth.
  C. Configure a redistribution policy.
  D. Configure ge-0/0/4 with a higher metric.
  D. Configure ge-0/0/4 with a higher metric.

• Question 105:

  Refer to the exhibit.

  

  Referring to the output shown in the exhibit, which statement is correct?

  A. The state is normal for a DR neighbor.
  B. The state is normal for a DRother neighbor
  C. An MTU mismatch exists between the OSPF neighbors.
  D. An area ID mismatch exists between the OSPF neighbors
  B. The state is normal for a DRother neighbor

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  Explanation/Reference:

  In OSPF, the state of the neighbor relationship is determined by the exchange of OSPF packets between routers1. The state "2Way" as shown in the exhibit indicates that bi-directional communication has been established

  between the two OSPF routers1. This is the normal state for a neighbor that is not the Designated Router (DR) or Backup Designated Router (BDR) on a broadcast, non-broadcast multi-access (NBMA), or point-to-multipoint network1. These

  neighbors are often referred to as "DRothers"1.

  Therefore, option B is correct.

• Question 106:

  What is the maximum allowable MTU size for a default GRE tunnel without IPv4 traffic fragmentation?

  A. 1496 bytes
  B. 1480 bytes
  C. 1500 bytes
  D. 1476 bytes
  D. 1476 bytes

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  Explanation/Reference:

  The maximum allowable MTU size for a default GRE tunnel without IPv4 traffic fragmentation is 1476 bytes1. This is because GRE packets are formed by the addition of the original packets and the required GRE headers1. These headers are 24- bytes in length and since these headers are added to the original frame, depending on the original size of the packet we may run into IP MTU problems1. The most common IP MTU is 1500-bytes in length (Ethernet)1. When the tunnel is created, it deducts the 24-bytes it needs to encapsulate the passenger protocols and that is the IP MTU it will use1. For example, if we are forming a tunnel over FastEthernet (IP MTU 1500)the IOS calculates the IP MTU on the tunnel as: 1500-bytes from Ethernet - 24-bytes for the GRE encapsulation = 1476-Bytes1.

• Question 107:

  What kind of filter would be written to protect control traffic destined for the switch?

  A. A filter applied to the default VLAN
  B. A filter applied to the native VLAN
  C. A filter applied to the management interface
  D. A filter applied to the loopback interface
  D. A filter applied to the loopback interface

• Question 108:

  Which two events cause a router to advertise a connected network to OSPF neighbors? (Choose two.)

  A. When an OSPF adjacency is established.
  B. When an interface has the OSPF passive option enabled.
  C. When a static route to the 224.0.0.6 address is created.
  D. When a static route to the 224.0.0.5 address is created.
  A. When an OSPF adjacency is established.
  D. When a static route to the 224.0.0.5 address is created.

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  Explanation/Reference:

  A is correct because when an OSPF adjacency is established, a router will advertise a connected network to OSPF neighbors. An OSPF adjacency is a logical relationship between two routers that agree to exchange routing information using the OSPF protocol1. To establish an OSPF adjacency, the routers must be in the same area, have compatible parameters, and exchange hello packets1. Once an OSPF adjacency is formed, the routers will exchange database description (DBD) packets, which contain summaries of their link-state databases (LSDBs)1. The LSDBs include information about the connected networks and their costs2. Therefore, when an OSPF adjacency is established, a router will advertise a connected network to OSPF neighbors through DBD packets. D is correct because when a static route to the 224.0.0.5 address is created, a router will advertise a connected network to OSPF neighbors. The 224.0.0.5 address is the multicast address for all OSPF routers3. A static route to this address can be used to send OSPF hello packets to all OSPF neighbors on a network segment3. This can be useful when the network segment does not support multicast or when the router does not have an IP address on the segment3. When a static route to the 224.0.0.5 address is created, the router will send hello packets to this address and establish OSPF adjacencies with other routers on the segment3. As explained above, once an OSPF adjacency is formed, the router will advertise a connected network to OSPF neighbors through DBD packets.

• Question 109:

  Your BGP router receives routes from two upstream ISPs: ISP A and ISP B. In this scenario, which change would you make to prefer routes from ISP A?

  A. Set the local-preference attribute for all routes received from ISP A to 200 while all routes received from ISP B use the default local-preference value of 100.
  B. Prepend the AS path to all routes received from ISP A while all routes received from ISP B use the default AS path value.
  C. Change the MED value for all routes received from ISP A to 1 while all routes from ISP B remain configured with no MED value.
  D. Set the local-preference attribute for all routes received from ISP A to 50 while all routes received from ISP B use the default local-preference value of 100.
  A. Set the local-preference attribute for all routes received from ISP A to 200 while all routes received from ISP B use the default local-preference value of 100.

• Question 110:

  Click the Exhibit button.

  

  Referring to the exhibit, Router 1 learns about Route X.

  Which statement is correct about Route X when using the default BGP advertisement rules?

  A. R1 will not advertise this route to any peers.
  B. R3 will not advertise this route to R4 or R5 without an explicit policy.
  C. R4 and R5 will not advertise this route to each other.
  D. R2 will not advertise this route to R3 without an explicit policy.
  C. R4 and R5 will not advertise this route to each other.